Contact imaging system

ABSTRACT

The contact imaging system allows the contact area of an object impressed upon the surface of the contact imaging system to emit light in a pattern corresponding to the contact area making it possible to render an image of the contact area. The contact imaging system has a luminescence layer on top of a transparent electrode. When the object to be imaged contacts the luminescence layer and is held at ground potential relative to the transparent electrode, an electric field is created in the luminescence layer in a pattern corresponding to the contact pattern. The electric field causes the luminescence layer to emit a light image of the contact pattern. The luminescence layer and the transparent electrode are adjacent to a light sensing layer. The light sensing layer receives the light generated at the luminescence layer, and converts that light into a corresponding electric signal. The light sensing element or layer can consist of a PN junction diode having a solar cell structure, a photo transistor, a camera, a scanner, a position sensitive detector, a charge couple device or a CMOS sensor. The contact imaging system can also include a stray light shield which may include a dark pigment to block stay light, and may also include a water repellent and/or abrasive resistant shield layer on top of the luminescence layer.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to a contact light emittingdevice, a method of manufacturing thereof and a contact input apparatususing thereof and more particularly, to a contact light emitting device,the method of manufacturing thereof and the contact input apparatususing thereof, capable of emitting a photo image of surface pattern of acontacted object upon contacting the object which acts as a ground andconverting and outputting the emitted photo image to image signal suchas an electrical image.

[0002] As a prior art, there is “an input apparatus using a fluorescentmaterial” filed by the present application on May 19, 1997 as the KoreaPatent Application No. 19282.

[0003] The input apparatus disclosed in the above application includes ametal electrode, a PN junction diode, a transparent conductive layer, anadhesive layer and a fluorescent film on a substrate formed with glassmaterials. The fluorescent film is formed with luminance material and isinputted with a various image pattern such as letters, figures, straightline, curve, etc., on the fluorescent film by way of pen or the like.

[0004] The fluorescent film is emitted to an image pattern inputted byway of a pen and the emitted light is converted from photo signal to theelectrical signal through the PN junction diode. That is, the inputsignal is converted and outputted with the electrical signal afterconverting the input image pattern to photo signal.

[0005] However, it is possible to input surface pattern by way of theinput apparatus. In other words, the input apparatus disclosed in theabove application can input information by way of pushing and moving thepen to the flashing body film but cannot input information just bypushing the film. The input apparatus disclosed by the application thuscannot be used for recognition of fingerprints.

[0006] Accordingly, the present invention is disclosed to solve theaforementioned problem and it is an object of the present invention toprovide a contact light emitting device by which an image of contactedarea as well as an exact rough surface of contacted area can be livelyexpressed and generated in a light emitting image just by touch orcontact to the light emitting apparatus.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a contactlight emitting device capable of emitting photo image of surface patternof a contacted object upon contacting the object which acts as a groundand a manufacturing method thereof.

[0008] It is other object of the present invention to provide a contactinput apparatus capable of converting and outputting the photo images tothe image signals such as electrical images.

[0009] Additional objects and advantages of the invention will set forthin part in the description which follows and in part will be obviousfrom the description, or may be learned by practice of the invention.The objects and advantages of the invention may be realized and attainedby means of the instrumentalities and combinations particularly pointedout in the appended claims.

[0010] To achieve the objects and in accordance with the purpose of theinvention, as embodied and broadly described herein, the contact lightemitting device of this invention comprises a transparent electrodelayer connected to one of alternating current power source terminals,luminescence layer for generating photo image such as surface pattern ofcontact surface by the electric field an formed between the transparentelectrode layer and a contacted object which acts as a ground, atransparent insulating layer for penetrating the photo image and formedunder the transparent electrode.

[0011] According to the present invention, a manufacturing method of acontact light emitting device of this invention comprising the steps of:forming a transparent insulating layer by using transparent insulatingmaterials, forming a transparent electrode layer by using a transparentconductive material above the transparent insulating layer, and mixing25-35 wt. % dielectric polymer paste, 25-29 wt. % retarder and 30-50 wt.% luminance powder doped by dopant above the transparent electrode layerand forming luminescence layer by using the mixed compound.

[0012] A contact input apparatus of this invention comprises atransparent electrode layer connected to one of alternating currentpower source terminals, luminescence layer for generating photo imagesuch as surface pattern of contact surface by the electric field andformed between the transparent electrode layer and a contacted objectwhich acts as a ground, a transparent insulating layer for penetratingthe photo image and formed under the transparent electrode, and a lightreceiving means for inverting an photo image occurred from theluminescence layer to an electrical signal received through thetransparent electrode layer and transparent insulating layer byattaching the transparent insulating adhesive material on a lowersurface of the transparent insulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other object, features, and advantages of the presentinvention will become more apparent from the following description ofthe preferred embodiments taken in conjunction with the accompanyingdrawings, in which:

[0014]FIG. 1 is a sectional view showing a structure of a contact lightemitting device in accordance with the present invention;

[0015]FIG. 2 is a sectional view showing a preferred embodiment of thecontact light emitting device of FIG. 1;

[0016]FIG. 3 is a table showing sample mixed ratios of a luminescencelayer illustrating a FIGS. 1 and 2;

[0017]FIG. 4 is a table showing mixed ratios of polymer pasteillustrated a FIG. 3;

[0018]FIG. 5 is a table showing sample mixed ratios of a penetratingcontrol layer illustrated at FIG. 2;

[0019]FIG. 6 is a table showing sample mixed ratios for manufacturing ashield layer illustrated a FIG. 2;

[0020]FIG. 7 is a table showing sample mixed ratios for manufacturing awater repellent layer illustrated at FIG. 2;

[0021]FIG. 8 is a sectional view of a structure of contact inputapparatus using contact light emitting device in accordance with thepresent invention; and

[0022]FIG. 9 is a sectional view showing a preferred embodiment of thecontact input apparatus using contact light emitting device inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The embodiments of a contact light emitting device according topresent invention will now be described in detail based on the drawings.

[0024]FIG. 1 is a sectional view showing a structure of a contact lightemitting device in accordance with the present invention. The contactlight emitting device of this invention comprises a transparentelectrode layer 2 connected to one of alternating current power sourceterminals, a luminescence layer 3 for generating photo-image such assurface pattern of contact surface 10 a by the electric field and formedbetween the transparent electrode layer 2 and a contacted object 10 uponcontacting the object 10 which acts as a ground, and a transparentinsulating layer 1 for penetrating the photo-image and formed under thetransparent electrode 2.

[0025] In the FIG. 1, the transparent electrode layer 2 is formed on thetransparent insulating layer 1 consisting of a transparent polymer. Thetransparent electrode layer 2 is formed with ITO (Indium Tin Oxide) andis connected to one of alternating current power source terminals. Also,a luminescence layer 3 is formed on the transparent electrode layer 2 tobe connected to one of the alternating current power source terminals.The luminescence layer 3 is formed with luminance powder doped withdopant and dielectric polymer.

[0026] The luminance powder is formed with at least one among twoelementary compound groups consisting of ZnS, SrS, and ZnO. The dopantdoped at the luminance powder is selected and mixed with at least oneamong dopant groups consisting of Mn, Cu, Cl, Al, I, Tb, and F.

[0027] The luminescence layer 3 is formed by adding a black pigment asan inorganic material for increasing contrast of photo image and is alsoformed by adding BaTiO₃ or other dielectric powders for increasingbrightness thereof.

[0028] The black pigment contained within the luminescence layer 3 isgenerally existed at non-luminescence portion formed between a luminancepowders. In case of emitting the luminance powder, the non-luminescenceportion is changed to the darker state than before and maintained withsaid state to predetermined minutes by adding the black pigment.Therefore, the luminescence layer 3 can be made with high visualcontrast of the photo image by providing a clear boundary between theluminance portion and the non-luminance portion.

[0029] An alternating current power source having 50-300V voltage and1K-3 MHz frequency is provided for the transparent electrode layer 2 forthe purpose of activating the luminescence layer 3 with color andbrightness which is determined by the dopant, the black pigment orBaTiO₃. The transparent electrode layer 2 is connected one of thealternating current power source terminals.

[0030] When the luminescence layer 3 is contacted by the object whichacts as a ground, an electric field is formed between the object 10 andthe transparent electrode layer 2 and a close circuit upon contactingthe object 10 to thereby emit the light.

[0031] That is, transparent electrode layer 2, luminescence layer 3 andthe object 10 are formed with a close circuit upon contacting the object10 which acts as a ground, and thus the electric field is formed at bothends of the luminescence layer 3.

[0032] When the luminescence layer 3 is activated by the electric field,a surface pattern of a contact surface 10 a of the object 10 isgenerated with the photo image. Also, the photo image is generated withwavelength corresponding to visual light region. The photo image isentered into a downwardly direction through the transparent electrodelayer 2 and the transparent insulating layer 1, and a transmitted photoimage is used with various usage after processing with an image signal.

[0033] Also, the luminescence layer 3 for generating the photo image isformed by adding a dielectric layer (not shown) at one of an upper or alower surface thereof. The dielectric layer is able to increase acapacitance of the contact light emitting device and thus the brightnessis increased in proportion to an increment of the capacitance. Thedielectric layer for increasing the luminance brightness is formed withone or multiple in order to insulate and shield alternating currentpower source.

[0034]FIG. 2 is a sectional view showing an embodiment of the contactlight emitting device illustrated at FIG. 1. As shown in FIG. 2, apenetrating control layer 4, a shield layer 5 and water repellent layer6 are gradually laminated on the luminescence layer 3.

[0035] The penetrating control layer 4 is formed between the luminancelayer 3 and the shield layer 5 for controlling exactly an amount of apenetrated black pigment to the luminance layer 3. The penetratingcontrol layer 4 is made of a dielectric polymer and BaTiO₃ so as toobtain a high dielectric ratio.

[0036] The penetrating control layer 4 is formed with a predeterminedthickness in order to control the amount of the black pigment includedat the shield layer 5. Also, the penetrating control layer 4 is acted asa dielectric layer by a dielectric polymer and BaTiO₃ powder. A shieldlayer 5 is formed between the penetrating control layer 4 and the waterrepellent layer 6.

[0037] The shield layer 5 is divided into a first shield layer 5 a andsecond shield layer 5 b for penetrating and forming a predeterminedamount of black pigment to the luminescence layer 3 through thepenetrating control layer 4 from the shield layer 5.

[0038] The second layer 5 b is prevented from emitting the light existedat an outside of the contact emitting layer.

[0039] A water repellent layer 6 which includes an abrasive and ahydrophobic characteristics having a repulsive force to the water, isformed on the shield layer 5.

[0040] When the object 10 is contacted with the water repellent layer 6,the electric field is formed between the contacted object 10 and thetransparent electrode layer 2 and thus generating the photo image by theelectric field. The photo image is entered with downward direct ionthrough the transparent electrode layer 2 and the transparent insulatinglayer 1 and the entered photo image is used as various ways according tothe contacted object 10.

[0041] Next, a manufacturing method of the contact light emitting deviceis described in more detail with reference to the accompanying drawing.The manufacturing method of the contact light emitting device ismanufactured by using a thick or a thin film processes, respectively.

[0042] First, the manufacturing method of the contact light emittingdevice manufactured by using the thick film is described as follows.

[0043] The manufacturing of the contact light emitting device of thepresent invention comprising the steps of forming the transparentinsulating layer by using transparent insulating materials, forming thetransparent electrode layer 2 by using a transparent conductive materialabove the transparent insulating layer 1, and mixing 25-35 wt. %dielectric polymer paste, 25-29 wt. % retarder and 30-50 wt. % luminancepowder doped by dopant above the transparent electrode layer 2 andforming a luminescence layer by using the mixed compound.

[0044] The transparent insulating layer 1 is formed with a transparentinsulating material containing a glass or a transparent polymer. Thetransparent insulating layer 1 is used as a substrate upon manufacturingthe contact light emitting device and is gradually laminated and formedwith the transparent electrode layer 2 and the luminescence layer 3 onthe transparent insulating layer 1.

[0045] The transparent electrode layer 2 formed on the transparentinsulating layer 1, is formed with a predetermined thickness by using atransparent conductive material as a paste type. The transparentconductive material for forming the transparent electrode layer 2, isformed by mixing an ITO (indium tin oxide) powder and a polymer.

[0046] After forming the transparent electrode layer 2, the luminescencelayer 3 is formed on the transparent electrode layer 2. As illustratedin FIG. 3, the luminescence layer 3 is formed with 25-35 wt. %dielectric polymer paste, 25-29 wt. % retarder, 30-50 wt. % luminancepowder doped by dopant on a transparent electrode layer 2 and forming aluminescence layer 3 busing the mixed compound.

[0047] The luminance powder containing at the luminescence layer 3, isformed with at least one of to elementary compound groups consisting ofZnS, SrS and ZnO (for example, one of II-IV family compound groups).Also, the dopant doped at the luminance powder is formed with at leastone of dopant groups consisting of Mn, Cu, Cl, Al, I, Tb, and F in orderto control brightness and color thereof.

[0048] The dopant can be able to determine a luminance color of theluminescence layer 3. The luminescence color of the luminescence layer 3is differently generated according to the dopant. Combinations of twoelementary compound groups and the dopants include ZnS+Cu, Mn, Cl;ZnS+Cu; ZnS+Cu,I; ZnS+Cu,Cl; ZnS+Cu,Al.

[0049] A binder to be used as luminance powder doped by the dopant, isdielectric polymer paste. As illustrated in FIG. 4, the dielectricpolymer paste is mixed and formed with 30 wt % Poly(vinylbutyral-co-vinyl alcohol-co-vinyl acetate) and 70 wt % ethylleneglycol mono-ethyl ether acetate. Also, it is formed by adding a retarderat the luminance powder. The retarder is formed with 20-60 μm thicknesson the transparent electrode layer 2 for preventing solidification ofthe luminescence layer 3 during screen printing process.

[0050] A dielectric layer (not shown) is added and formed on upper orlower surfaces of the luminescence layer 3 after forming theluminescence layer 3 above the transparent electrode layer 2. Thedielectric layer is added and formed on one of the upper surface, thelower surface and both surfaces of the luminescence layer 3 aftermanufacturing the dielectric material as a paste type. The dielectriclayer is formed as one or multiple layers.

[0051] As illustrated in FIG. 2, penetrating control layer 4, shieldlayer 5 and water repellent layer 6 are formed on the luminescence layer3 for obtaining high brightness and having an abrasive or durabilitycharacteristics.

[0052] The dielectric polymer paste having a predetermined thickness isformed on the luminescence layer 3 before forming the penetratingcontrol layer 4 on the luminescence layer 3. The polymer pastepenetrates the luminescence layer 3 and coats the surface of theluminance powder to be formed the luminescence layer 3. The surface ofthe luminance powder is coated by the polymer so that the bulk of lightoccurred from the luminescence layer 3 cannot be dispersed to adistance. The light is remained by the polymer film coated at thesurface of the luminance powder so that a good photo image can beobtained upon generating photo image.

[0053] Small quantities of black pigment and BaTiO₃ powder havingmolecular size not exceeding 1 μm, are added at the luminescence layer3. The BaTiO₃ powder increases a dielectric ratio and the black pigmentis to increase a non-luminance portion between the luminance portionsand thus increasing the contrast of the photo image.

[0054] After finishing the coating process for covering the surface oftile luminance power, it is dried at a dry oven (not shown in order tovolatilize and solidify the retarder. When the dry process is finished,the luminescence layer 3 is heated and pressurized under 100-200° C. andthus increasing a fineness of a membrane. After finishing the coatingand drying processes, a penetrating control layer 4 is added and formed.

[0055] The penetrating control layer 4 is formed for controlling anamount of the black pigment at the process which penetrates the blackpigment contained at a shield layer 5 to the luminescence layer 3.

[0056] As illustrated in FIG. 5, the mixing ratio of penetrating controllayer 4 is formed with 11-26 wt. % of polymer paste, 11-22 wt. % ofretarder, 15-26 wt. % of plastic material and 26-63 wt. % of BaTiO₃powder whose molecular size dose not exceed 1 μm. One ofN-ethyl-P-toluenesulfonamide, dimethylformamide, dimethylphthalate forforming the luminescence layer 3 and the penetration control layer 4 isselected and added to as the plastic material.

[0057] The penetrating control layer 4 having a thickness ofapproximately 5 μm is easily penetrated by the pigment contained at theshield layer 5 to the luminescence layer 3. In case of using theN-ethyl-P-toluenesulfonamide, the penetrating control layer 4 havinghigh dielectric ratio is formed and is increased to the fineness of themembrane after heating and pressurizing under 100-200° C.

[0058] After forming the penetrating control layer 4, the shield layer 5is formed above the penetrating control layer 4. If the penetratingcontrol layer 4 is not formed, the shield layer 5 is directly formed onthe luminescence layer 3.

[0059] As illustrated in FIG. 6, the shield layer 5 is mixed and formedwith 1-5 wt. % black pigment, 5-30 wt. % polyurethane, 15-23 wt. %ethyllene glycol monoethyl ether acetate, 50-71 wt. % xylene and BaTiO₃powder whose molecular size does not exceeding 1 μm. The BaTiO₃ powderhas more high dielectric ratio than the shield layer 5.

[0060] The shield layer 5 whose thickness does not exceeding 10 μm isformed. The shield layer 5 includes a first shield layer 5 a penetratingand forming a predetermined amount of black pigment to the luminescencelayer 3 wherein the first shield layer 5 a has a lower viscosity than asecond shield layer 5 b, and a second shield layer 5 b for shielding ancuter light and formed above the first shield layer 5 a. In the firstshield layer 5 a, the black pigment is penetrated and moved to theluminescence layer 3 through the penetrating control layer 4.

[0061] After forming the first shield layer 5 a, the second shield layer5 b is formed. The black pigment contained at the second shield layer 5b is not to penetrate a light existed at an outer of the contact lightemitting device into the luminescence layer 3. After forming the firstshield layer 5 a and the second shield layer 5 b in regular sequence,the first and second shield layers 5 a, 5 b are increased to thefineness of the membrane by heating and pressurizing under 100-200° C.after polymerizing the first and second shield layers 5 a, 5 b at a dryoven.

[0062] A water repellent layer 6 whose thickness does not exceeding 5 μmis formed above the shield layer 5 constructed as the first shield layer5 a and the second shield layer 5 b. The water repellent layer 6 isformed with a strong water repellent upon contacting one of a water, amoisture and an object and is also formed with a good internal abrasionfor preventing an abrasion upon contacting the object.

[0063] As illustrated in FIG. 7, the water repellent layer 6 is mixedand formed with 6-35 wt. % polyurethane, 15-23 wt. % ethylene glycolmono ethyl ether acetate, 50-71 wt. % xylene and BaTiO₃ on the shieldlayer and forming a water repellent layer.

[0064] Upon forming the penetrating control layer 4, the polyurethanecan be replaced with a poly(vinyl butyral-co-vinyl alcohol-co-vinylacetate).

[0065] The above mentioned method is a manufacturing method of thecontact light emitting device using a thick film to be formed by using ascreen printing method or a spin coating method.

[0066] A plain degree of the membrane of the spin coating method isimproved rather than that of the screen printing method. The contactlight emitting device of the present invention is also manufactured byusing thin film.

[0067] Each of materials of the layers for forming the contact lightemitting device is formed with solidification. That is, each of thelayers is formed with sputtering target or solidification in order tomanufacture the contact light emitting device with thin film.

[0068] As illustrated in FIG. 1, the transparent electrode layer 2having 0.05-0.1 μm thickness is formed after sputtering the ITOmanufactured by the sputtering target on the transparent insulatinglayer 1. After forming the transparent electrode layer 2, theluminescence layer 3 having 0.5-1.0 μm thickness is formed by sputteringthe sputtering target for forming the luminescence layer 3 on thetransparent electrode layer 2.

[0069] The mixing example of the target for forming the luminescencelayer 3 is formed with ZnS+Mn, Cl; ZnS+Tb, F; SrS+Ce, etc. Aconcentration of the dopant to be doped at the luminance powdermanufactured by the sputtering method is 0.1-2.5 atomic %.

[0070] A dielectric layer (not shown) formed at least one surface of theluminescence layer 3 is used as a target with a high dielectricmaterial. The dielectric layer having 0.3-0.5 μm thickness is formed bysputtering as a target with the high dielectric material on thetransparent electrode layer 2 or the luminescence layer 3. After formingthe shield layer 5 and the water repellent layer 6 by using thesputtering target, the shield layer 5 and the water repellent layer 5are formed with sputtering order, respectively. Also, the contact lightemitting device is also manufactured by an evaporation method afterforming material of each layer with solidification in replace of thesputtering method.

[0071] Now, a contact input apparatus for converting and outputting thephoto image occurred at the contact light emitting device manufacturedby using thick film or thin film methods to the image signal such as anelectrical signal will be described in more detail with reference toaccompanying drawings.

[0072]FIG. 8 is a sectional view, for illustrating the structure of thecontact input apparatus using the contact light emitting device of thepresent invention and FIG. 9 is a sectional view shown an embodiment ofthe contact input apparatus using the contact light emitting device ofthe present invention. As shown in FIGS. 8 and 9, when the object 10 iscontacted with the transparent electrode layer 2 connected to one ofalternating, current power source terminals, the electric field isformed between the transparent electrode layer 2 connected to one ofalternating current power terminals and the contacted object 10.

[0073] The contact input apparatus including the transparent electrodelayer 2 connected to one of alternating current power source terminals,luminescence layer 3 for generating photo-image such as surface patternof contact surface by electric field and formed between the transparentelectrode layer 2 and a contacted object 10 which acts as a ground, atransparent insulating layer 1 for penetrating the photo-image andformed under the transparent electrode layer 2, and a light receivingelement 9 for inverting an photo-image occurred from the luminescencelayer 3 to an electrical signal received through the transparentelectrode layer 2 and the transparent insulating layer 1 by attachingthe transparent insulating adhesive material 7 on a lower surface of thetransparent insulating layer 1.

[0074] Referring to FIG. 1, the contact input apparatus is constructedwith the transparent insulating layer 1, the transparent electrode layer2 and luminescence layer 3. Also, the penetrating control layer 4, theshield layer 5 and the water repellent layer 6 are formed on theluminescence layer 4 as shown in FIG. 2. A contact input apparatus canbe constructed with a constructing element of the contact light emittingdevice shown in FIGS. 1 and 2 and the light receiving element 9 as thetransparent insulating adhesive material 7.

[0075] The contact input apparatus is formed by attaching thetransparent insulating of the contact light emitting device and by usingtransparent insulating adhesive material 7 to the light receivingelement 9 formed on a substrate 8. The light receiving element 9 formedon the substrate 8 is a PN junction diode.

[0076] For converting the received photo-image to the electrical signal,the PN junction diode is formed with a solar cell structure andregularly laminated to a lower electrode layer 9 a formed with aconductive metal on the substrate 8, N-type amorphous silicon layer 9 b,an intrinsic amorphous silicon layer 9 c, P-type amorphous silicon layer9 d and an upper transparent electrode layer 9 e, respectively.

[0077] The electric field is formed by applying a predetermined reverseddirection voltage to the PN junction diode. A pair of electron holeswhich generates in the PN junction diode, is separated by the receivedphoto-image and the electric signal according to the separatedphoto-image is occurred. The photo-image is received at P-type amorphoussilicon layer 9 d so that intrinsic amorphous silicon layer 9 c such asdepletion layer is also occurred. Since the pair of electron holes isseparated by the electric field, the holes are moved to the uppertransparent electrode layer 9 e through the P-type amorphous siliconlayer 9 d and electron is moved to the lower electrode layer 9 a throughthe N-type amorphous silicon layer 9 b and an electric signal accordingto the photo-image is occurred.

[0078] The light receiving element is formed with two dimensional arrayfor receiving the photo-image occurred at the contact light emittingdevice. In the light receiving element having the two dimensional array,an array number of the light receiving element is determined by ananalysis is performance of the contacted object 10 and a resolution ofthe contacted surface 10 a of the object 10 is differently formed to thearray number of the light receiving element. The light receiving elementsuch as PN junction diode can be replaced with CCD(Charge CoupledDevice) sensor or CMOS(Complementary Metal Oxide Semiconductor) imagesensor.

[0079] A photo-image generated at the contact light emitting deviceformed by using the luminance powder consisted with two elementarycompound groups is converted to the electric signal by the lightreceiving element. Thus, a pattern of a contact surface of the object isconverted to an image signal.

[0080] When an object (for example, a fingerprint formed at a finger ofthe human) is loaded on the contact surface of the contact lightemitting device, a concave and convex pattern formed at the contactedobject is automatically extracted from photo-image and converted into animage signal. According to the present invention, the clear surfacepattern of a contacted object can be obtained by generating thephoto-image such as a pattern of the object which acts as a ground andconverting the photo-image to an image signal such as an electricsignal. Thus, the present invention can be applied to a fingerprintidentification system, which compares the difference between a storedfingerprint data and a detected fingerprint. Also, the present inventionenables a reduced manufacturing cost by using a screen printing method.

[0081] The invention is in no way limited to the embodiment describedhereinabove. Various modifications of the disclosed embodiment as wellas other embodiments of the invention will become apparent to personsskilled in the art upon reference to the description of the invention.It is therefore contemplated that the appended claims will cover anysuch modifications or embodiments as fall within the true scope of theinvention.

1. A contact imaging system, comprising: a light sensing element; atransparent insulating layer overlaying said light sensing element; atransparent electrode layer overlaying said transparent insulatinglayer; a luminescence layer overlaying said transparent electrode layer;and a stray light shield layer overlaying said luminescence layer,wherein the luminescence layer and the electrode layer are configuredsuch that an electric field can be applied between an object to beimaged and said transparent electrode layer.
 2. The contact imagingsystem according to claim 1, further comprising a transparent adhesivedisposed between said light sensing element and said transparentinsulating layer.
 3. The contact imaging system according to claim 1,wherein said light sensing element comprising a PN junction diode. 4.The contact imaging system according to claim 3, wherein said PNjunction diode comprises: a lower electrode; an N-type silicon layeroverlaying said lower electrode; an intrinsic silicon layer overlayingsaid N-type silicon layer; a P-type silicon layer overlaying saidintrinsic silicon layer; and, a transparent electrode overlaying saidP-type silicon layer.
 5. The contact imaging system according to claim4, wherein said PN junction diode is configured to be biased by areversed direction voltage.
 6. The contact imaging system according toclaim 1, wherein said light sensing element comprises a charge coupleddevice.
 7. The contact imaging system according to claim 1, wherein saidlight sensing element comprises a complementary metal oxidesemiconductor (CMOS) image sensor.
 8. The contact imaging systemaccording to claim 1, wherein said light sensing element comprises aphoto transistor.
 9. The contact imaging system according to claim 1,wherein said light sensing element comprises a position sensitivedetector.
 10. The contact imaging system according to claim 1, whereinsaid light sensing element comprises a camera.
 11. The contact imagingsystem according to claim 1, wherein said light sensing elementcomprises a scanner.
 12. The contact imaging system according to claim1, wherein said luminescence layer includes a dark pigment that acts toenhance contrast.
 13. The contact imaging system according to claim 12,further comprising a penetrating control layer formed between saidluminescence layer and said stray light shield layer, wherein said straylight shield layer includes a dark pigment, and wherein said penetratingcontrol layer is configured to limit an amount of said dark pigment thatpasses from said stray light shield layer to said luminescence layer.14. The contact imaging system according to claim 13, wherein said straylight shield layer comprises: a first layer adjacent the penetratingcontrol layer that includes said dark pigment; and a second layeroverlying said first layer, wherein said second layer is configured toblock exterior light.
 15. The contact imaging system according to claim1, wherein said light sensing elements comprises a two dimensional arrayof light sensing elements.
 16. A contact imaging system, comprising: alight sensing element; a transparent insulating layer overlaying saidlight sensing element; a transparent electrode layer overlaying saidtransparent insulating layer; a luminescence layer overlaying saidtransparent electrode layer; and a protective layer overlaying saidluminescence layer, wherein said luminescence layer and said electrodelayer are configured such that an electric field can be applied betweenan object to be imaged and said transparent electrode layer.
 17. Thecontact imaging system according to claim 16, wherein said light sensingelement comprises a PN junction diode.
 18. The contact imaging systemaccording to claim 17, wherein said PN junction diode comprises: a lowerelectrode; an N-type silicon layer overlaying said lower electrode; anintrinsic silicon layer overlaying said N-type silicon layer; a P-typesilicon layer overlaying said intrinsic silicon layer; and, atransparent electrode overlaying said P-type silicon layer.
 19. Thecontact imaging system according to claim 16, wherein said PN junctiondiode is configured to be biased by a reversed direction voltage. 20.The contact imaging system according to claim 16, wherein said lightsensing element comprises a charge coupled device.
 21. The contactimaging system according to claim 16, wherein said light sensing elementcomprises a complementary oxide semiconductor image sensor.
 22. Thecontact imaging system according to claim 16, wherein said light sensingelement comprises a photo transistor.
 23. The contact imaging systemaccording to claim 16, wherein said light sensing element comprises aposition sensitive detector.
 24. The contact imaging system according toclaim 16, wherein said light sensing element comprises a camera.
 25. Thecontact imaging system according to claim 16, wherein said light sensingelement comprises a scanner.
 26. The contact imaging system according toclaim 16, wherein said protective layer is hydrophobic.
 27. The contactimaging system according to claim 16, wherein said protective layer isabrasion resistant.
 28. The contact imaging system according to claim16, further comprising a shield layer disposed between said protectivelayer and said luminescence layer, wherein said shield layer isconfigured to block exterior light.
 29. The contact imaging systemcomprising: a light sensing element; a transparent insulating layeroverlaying said light sensing element; a transparent electrode layeroverlaying said transparent insulating layer; and a luminescence layeroverlaying said transparent electrode layer, wherein the electrode layeris configured such that an electric field can be applied between anobject to be imaged and said transparent electrode layer, and whereinsaid electric field causes said luminescence layer to luminesce when theobject to be imaged is brought adjacent to said luminescence layer. 30.The contact imaging system according to claim 29, further comprising atransparent adhesive disposed between said light sensing element andsaid transparent insulating layer.
 31. The contact imaging systemaccording to claim 29, wherein said light sensing element comprises a PNjunction diode.
 32. The contact imaging system according to claim 31,wherein said PN junction diode comprises: a lower electrode; an N-typesilicon layer overlaying said lower electrode; an intrinsic siliconlayer overlaying said N-type silicon layer; a P-type silicon layeroverlaying said intrinsic silicon layer; and, a transparent electrodeoverlaying said P-type silicon layer.
 33. The contact imaging systemaccording to claim 29, wherein said light sensing element comprises acharge coupled device.
 34. The contact imaging system according to claim29, wherein said light sensing element comprises a complementary metaloxide semiconductor image sensor.
 35. The contact imaging systemaccording to claim 29, wherein said light sensing element comprises aphoto transistor.
 36. The contact imaging system according to claim 29,wherein said light sensing element comprises a position sensitivedetector.
 37. The contact imaging system according to claim 29, whereinsaid light sensing element comprises a camera.
 38. The contact imagingsystem according to claim 29, wherein said light sensing elementcomprises a scanner.
 39. The contact imaging system of claim 29, furthercomprising: a shield layer that includes a dark pigment; and apenetrating control layer located between said shield layer and saidluminescence layer, wherein said penetrating control layer is configuredto limit an amount of the dark pigment in the shield layer that migratesto the luminescence layer.
 40. The contact imaging system of claim 29,further comprising a protective layer overlaying the shield layer,wherein the protective layer is abrasion resistant and repels moisture.